The Evolution Revolution

Charles Darwin and the Rise of Modern Science

Early 19th Century

• Science on the rise

• Structure of the physical universe better understood.

• Biology poorly understood

Big Question

• What is the origin of species?

• Divine Creation: God created all living things as they are and they do not change over time. (prevailing view)

Evolution

• A radical idea that gains support in the 18th Century.

• Geologist find evidence for an old and changing Earth.– Mountain building and erosion patterns.– Fossils in strange places and strange fossils.

Lamarck’s Concept of Evolution

Jean-Baptiste Lamarck

(1744-1829)• Made many important

contributions to biology (Medicine, Botany, Invertebrate Zoology).

• One of the first scientist to become convinced evolution happens.

Lamarck’s Concept of Evolution

• Environmental changes occur.• Changed environment alters the needs of living

things.• These altered needs lead to changes in behavior.• Altered behavior means that some structures/organs

will have more or less use.

→

↓

Evolution of the Giraffe

Okapi

The Life of Darwin(1809-1882)

• Washes out of Medical School.

• Completes Bachelor’s Degree and is preparing to enter clergy.

• Much more interested in being a “naturalist”.

• Receives offer to sail on the HMS Beagle

Voyage of the Beagle(1831-36)

Mission: To Map theCoastline of S. America

Capt. Robert Fitzroy

Darwin’s Landing at Buccaneer Cove, Santiago Island“Nothing could be less inviting than the first appearance.” --Charles Darwin

High Number of Endemics

• Most species are endemic (i.e. found only on the Galapagos). – 42% of the plants– 100% of the land reptiles– 26% of sea birds– 75% of land birds– 82% of mammals

Land Iguana (South Plaza Island)

Galapagos Tortoise (Geochelone elephantopus)

Scientific Method

• Set of rules used to study natural phenomena.

• These rules are used in an effort to focus research in the most useful direction.

• They also (hopefully) keep us from jumping to appealing but erroneous conclusions.

Scientific MethodObservations

Hypothesis

Experimentation

Hypothesis revision

New Experiments

Theories and Models

Scientific Method

Scientist use this method to avoid:

1. Reliance on authority or revealed wisdom.

2. Over use of “common sense”.

3. Acceptance of anecdotal data.

4. Accepting an hypothesis with inadequate testing.

Darwin’s Scientific Method

• Massive Observations– Selective breeding– Observations of other scientists– Beagle observations

• Development of a Hypothesis– Evolution: Change over time– Natural Selection as the Mechanism

Development of a Theory

• Theory: A hypothesis that has been thoroughly tested and never falsified.

• Accepted to be true and used as a basis for future hypotheses– e.g. Einstein’s theory of Relativity.

The Theory of Evolution

• Change over time: Thoroughly documented and demonstrated– anatomical evidence– fossil evidence– development– molecular evidence

• Natural Selection: Shown to be the major way in which this change occurs. (but not the only way)

The Controversy

• Copernicus, Galileo, Newton, and Kepler changed the way we view the functioning of our world.– Earth is not the center of the universe

• Darwin changed the way we view creation (life) itself.– Humans are not the center of the Earth

New View of Life(the Moran version)

• Humans are part of a long (billions of years) and fascinating history of life.

• All life is unique and special

• We are creations of this world but the world was not created for us.

Slow to publish: Why so long?

• Anguish

• Illness

• Slow development of ideas

• Collection of a wealth of evidence

Anguish

• Social class– Respectability– Evolution subversive - against his class

• Religous considerations– especially worried about hurting wife Emma

who grieved for his soul

• Scientific prejudice against “speculation”

• “Like confessing a murder.”

Illness

• Sea sickness• Problems throughout life

– violent shivering, vomiting, exhaustion, palpitations, hands trembling, head swimming, sleeplessness, headaches, flatulance, stomach problems, ringing of ears, fainting, copious palid urine

• In 1841 could work “an hour or two a couple of days a week.”

• Chaga’s disease or just nervous?

Slow to publish: Why so long?

• Anguish

• Illness

• Slow development of ideas

• Detailed analysis, collection of a wealth of evidence

– pigeons– barnacles

Alfred Russel Wallace

• Thought of natural selection (1959)• Wrote to Darwin• Darwin had been working on book• Published a “letter” jointly• Wallace didn’t

– put in the hard yards collecting and documenting evidence to support theory

– remain in favour of the theory

• Darwin did!